#coeff. restituzione=vel dopo impatto/vel prima impatto #IC 0.95 dati<- c( 0.8411, 0.8125, 0.8532, 0.7983, 0.8282, 0.8191, 0.8750, 0.8483, 0.8042, 0.8359, 0.8182, 0.8580, 0.8276, 0.8730, 0.8660 ) #tabella di lavoro #media<-sum(dati)/n table<-cbind(dati,dati^2) #,(dati-media),(dati-media)^2) colnames(table)<-c("dati","dati^2") #,"scarti","scarti^2") table sommetable<-colSums(table) sommetable TABLE<-rbind(table,sommetable) rownames(TABLE)<-c(1:15,"somme") TABLE n<-15 med<-sommetable[1]/n S2<-(sommetable[2]/n-med^2 )*n/(n-1) #oppure i comandi #mean(dati) #var(dati) #sigma noto#alpha=0.95############################## varianza<-0.0005 media<-mean(dati)#sum(dati)/n n<-length(dati) z0975<-qnorm(1-0.05/2) L<-media-z0975*sqrt(varianza)/sqrt(n) U<-media+z0975*sqrt(varianza)/sqrt(n) IC095<-c(L,U) IC095 #numerosità necessaria per dimezzare ampiezza intervallo d<-(U-L)/2 nn<-( 2*z0975*sqrt(varianza)/d )^2 #per ridurla a un quarto d<-(U-L)/4 nnnn<-( 2*z0975*sqrt(varianza)/ d )^2 #sigma non noto############################################ varianza<-var(dati) media<-mean(dati)#sum(dati)/n n<-length(dati) t0975<-qt(1-0.05/2,n-1) L<-media-t0975*sqrt(varianza)/sqrt(n) U<-media+t0975*sqrt(varianza)/sqrt(n) IC095<-c(L,U) IC095 #######intervalli unilaterali [L Inf) ) alpha<-1-(0.95) zsx<-qt(alpha,n-1) L<-media+zsx*sqrt(varianza)/sqrt(n) c(L,Inf) #ESERCIZIO intervallo (-Inf U] U<-media+qt(0.95,n-1)*sqrt(varianza)/sqrt(n) c(-Inf,U) #IC per varianza alpha 0.95 c025<-qchisq(0.025,n-1) c0975<-qchisq(0.975,n-1) l<-(n-1)*varianza/c0975 u<-(n-1)*varianza/c025 ic<-c(l,u) ic ########################TEST DI IPOTESI #########test valore atteso uo=0.84 alpha 0.05 varianza non nota varianza<-var(dati) media<-mean(dati) n<-length(dati) test<-(media-0.84)/sqrt(varianza)*sqrt(n) #alternativa dx c<-qt(0.95,n-1) #decisione test>=c P<-1-pt(test,n-1) P<=0.05 #alternativa sx c<-qt(0.05,n-1) #decisione test<=c P<-pt(test,n-1) P<=0.05 #alternativa bil c<-qt(0.975,n-1) #decisione test<=-c|test>=c #########test valore atteso uo=0.84 alpha 0.05 varianza nota varianza<-0.0005 test<-(media-0.84)/sqrt(varianza)*sqrt(n) #alternativa dx c<-qnorm(0.95) #decisione test>=c #alternativa sx c<-qnorm(0.05) #decisione test<=c #alternativa bil c<-qnorm(0.975) #decisione test<=-c|test>=c ######################################test varianza sigma20=0.002 n<-length(dati) varianza<-var(dati) test<-(n-1)*varianza/0.002 #alternativa DX alpha=0.05 c<-qchisq(0.95,n-1) test>=c pvalue<-1-pchisq(test,n-1) pvalue #alternativa SX alpha=0.05 c<-qchisq(0.05,n-1) test<=c pvalue<-pchisq(test,n-1) pvalue #alternativa bil c1<-qchisq(0.025,n-1) c2<-qchisq(0.975,n-1) test<=c1|test>=c2 pvaluesx<-pchisq(test,n-1) pvaluedx<-(1-pchisq(test,n-1)) pvalue<-2*min(pvaluesx,pvaluedx) pvalue #######################IC########################### #lenticchie spa peso confezioni di lenticchie normale sigma=12.6 #n=32 ,media campionaria 97.3,1-alpha=0.99 IC per mu m<-97.3 n<-32 sigma<-12.6 p<-1-(1-0.99)/2 #1-alpha/2 z<-qnorm(p) L<-m-z*sigma/sqrt(n) U<-m+z*sigma/sqrt(n) c(L,m,U) #illimitato sx L<--Inf U<-m+qnorm(0.99)*sigma/sqrt(n) c(L,U) #illimitatodx U<-Inf L<-m+qnorm(1-0.99)*sigma/sqrt(n) c(L,U) #p=0.001 prob di sovrastima z_l<-qnorm(0.001) L<-m+z_l*sigma/sqrt(n) #p<-pnorm(z_l) z_u<-qnorm(0.99+0.001) U<-m+z_u*sigma/sqrt(n) c(L,U) #####1-p=1-0.999=0.001 prob sottostima z_u<-qnorm(0.999) z_l<-qnorm(1-0.99-(1-p)) U<-m+z_u*sigma/sqrt(n) L<-m+z_l*sigma/sqrt(n) c(L,U) ###################################################################### #n=40 impianti irrigazione simili media consumi annui 750 litri e S=31.3 #1-alpha=0.99 IC per conumo atteso annuo n<-40 m<-750 s<-31.3 p<-1-(1-0.99)/2 z<-qt(p,n-1) L<-m-z*s/sqrt(n) U<-m+z*s/sqrt(n) c(L,m,U) #per varianza normale ################################################################################ #7 pezzi su 90 risultano difettosi, 1-alpha=0.95, IC pe rprobabilitàpezzo difettoso P<-7/90 n<-90 p<-1-(1-0.95)/2 z<-qnorm(p) L<- P-z*sqrt( P*(1-P) )/sqrt(n) U<- P+z*sqrt( P*(1-P) )/sqrt(n) c(L,P,U) ################################################################################## #Il peso sfere prodotte è una vc normale. In un campione di 41 sfere S^2=15.1 #1-alpha=0.95 IC n<-41 S2<-15.1 p<-(1-0.95)/2 P<-1-(1-0.95)/2 z_p<-qchisq(p,n-1) z_P<-qchisq(P,n-1) L<-(n-1)*S2/z_P U<-(n-1)*S2/z_p c(L,S2,U) ######################################################################################## #si è interessti a diametro sfere prodotte. Diametri vc normali con sigma=3.1 #si vuole IC per valore atteso diametri 1-alpha=0.95 d=0.3 Cosa deve essere n sigma<-3.1 d<-0.3 p<-1-(1-0.95)/2 z<-qnorm(p) n<-(2*z*sigma/d)^2 ceiling(n) ######################################################################################### #intervallo confidenza probabilità pezzi difettosi 1-alpha=0.95 d=0.06 d<-0.06 p<-1-(1-0.95)/2 z<-qnorm(p) n<-(2*z*1/4/d)^2 ceiling(n) #######################TEST########################### #media campionaria pesi prodotto numerosità n=11 #sigma=1.2 u0=7.3 verso tre alternative alpha=0.05 dati<-c(7.8,6.6,6.5,7.4,7.3,7,6.4,7.1,6.7,7.6,6.8) alpha<-0.05 m<-mean(dati) n<-length(dati) sigma<-1.2 u0<-7.3 #altern dx test<-(m-u0)/sigma*sqrt(11) zdx<-qnorm(1-alpha) #regola test>=zdx pvalue<-1-pnorm(test) pvalue<=alpha #altern sx zsx<-qnorm(alpha) #regola test<=zsx pvalue<-pnorm(test) pvalue<=alpha #alternbil zbil<-qnorm(1-alpha/2) #regola test<=-zbil|test>=zbil pvalue<-2*(1-pnorm(abs(test))) pvalue<=alpha ####come sopra ma varianza non nota u0<-7.3 alpha=0.05 dati<-c(7.8,6.6,6.5,7.4,7.3,7,6.4,7.1,6.7,7.6,6.8) m<-mean(dati) varianza<-var(dati) n<-length(dati) u0<-7.3 test<-(m-u0)/sqrt(varianza)*sqrt(11) zdx<-qt(1-alpha,n-1) #regola test>=zdx pvalue<-1-pt(test,n-1) pvalue<=alpha #altern sx zsx<-qt(alpha,n-1) #regola test<=zsx pvalue<-pt(test,n-1) pvalue<=alpha #alternbil zbil<-qt(1-alpha/2,n-1) #regola test<=-zbil|test>=zbil pvalue<-2*(1-pt(abs(test),n-1)) pvalue<=alpha ########################################################### #dati esercizio sopra testare sigma2=1.44 alpha=0.05 alt bilat test=(n-1)*var(dati)/1.44 chi1<-qchisq(0.05/2,n-1) chi2<-qchisq(1-0.05/2,n-1) test<=chi1|test>=chi2 ########test su proporzione test per probabilità #7 pezzi su 90 risultano difettosi, alpha=0.01, test prprobabilitàpezzo difettoso #p0=0.01 alternativa dx #dati P<-7/90 n<-90 p0<-0.05 # test<-(P-p0)/sqrt(p0*(1-p0))*sqrt(n) z099<-qnorm(0.99) test>=z099 (1-pnorm(test))<=0.01 #############################potenza #media campionaria pesi prodotto numerosità n=11 #sigma=1.2 u0=7.3 alpha=0.01 unilat dx potenza verso ua=8 u0<-7.3 ua<-8 sigma<-1.2 n<-11 la<-(ua-u0)/sigma z099<-qnorm(0.99) zpot<-z099-la*sqrt(n) pot<-1-pnorm(zpot) #n per pot=0.90 zstar<-qnorm(1-0.90) n<-( (z099-zstar)/la )^2 ceiling(n) #media campionaria pesi prodotto numerosità n=11 #sigma=1.2 u0=7.3 alpha=0.01 unilat sx potenza verso ua=6.6 u0<-7.3 ua<-6.6 sigma<-1.2 n<-11 la<-(ua-u0)/sigma z001<-qnorm(0.01) zpot<-z001-la*sqrt(n) pot<-pnorm(zpot) #n per pot=0.90 zstar<-qnorm(0.9) n<-( (z001-zstar)/la )^2 ceiling(n) ########################### #############################potenza #media campionaria pesi prodotto numerosità n=11 #sigma non noto la=0.58 alpha=0.01 unilat dx potenza verso ua=8 n<-39 la<-0.58 z099<-qt(0.99,n-1,0) alpha<-1-pt(z099,n-1,0) nc<-la*sqrt(n) pot<-1-pt(z099,n-1,nc) pot #media campionaria pesi prodotto numerosità n=11 #sigma non noto la=-0.58 alpha=0.01 unilat sx potenza verso ua=8 n<-39 la<--0.58 z001<-qt(0.01,n-1,0) alpha<-pt(z001,n-1,0) nc<-la*sqrt(n) pot<-pt(z001,n-1,nc) pot ############tet 2 campioni########################################################################## #library(xtable) x<-c(9.89 , 10.05 , 9.01 , 9 , 9.9 , 6.84 , 9.95 ,8.8 , 8.8 , 7.9 , 9 , 11) y<-c( 10.33 ,8.95 , 10.5 ,7.7 , 9.6 , 8 , 8.6, 9.8 , 9 , 8.8 , 9.2 ,10) t.test(x,y,var.equal=TRUE,conf.level=0.99,alterntive="two.sided") t.test(x,mu=8,alternative="greater",conf.level=0.99) #calcoli diretti mx<-mean(x) sx<-var(x) my<-mean(y) sy<-var(y) #ancora più elementary #mx2<-( sum(x^2)/12-(sum(x)/12)^2 )*12/11 #test due campioni ss<-(11*sx+11*sy)/22 stxy<-(mx-my)/sqrt(ss*(1/12+1/12)) stxy p<-(1-0.99)/2 z099<-qt(p,22) stxy<=-z099|stxy>=z099 PBIL<-2*(1-pt(abs(stxy),22)) PBIL PBIL<=1-0.99 #se sigma2^2=1 noto sigma2<-1 stxy<-(mx-my)/sqrt(sigma2*(1/12+1/12)) stxy p<-1-(1-0.99)/2 z099<-qnorm(p) stxy<=-z099|stxy>=z099 PBIL<-2*(1-pt(abs(stxy),22)) PBIL PBIL<=1-0.99 F<-sx/sy p025<-qf(0.025,11,11) p975<-qf(0.975,11,11) F<=p025|F>=p975 #library(xtable) #colnames(working.table)<-c("x","y","x^2","y^2","x*y") #edit(working.table) #workreg<-xtable(TABLE,caption="IC TEST-tabella di lavoro",digits=4) #print(workreg,file="IC.tex")